[pve-devel] Default cache mode for VM hard drives

Dietmar Maurer dietmar at proxmox.com
Thu May 28 09:31:35 CEST 2015

> I have just done the same test with mdadm and not DRBD. And what I found
> that this problem was reproducible on the software raid too, just as it was
> claimed by Lars Ellenberg. It means that problem is not only related to
> DRBD but to O_DIRECT mode generally when we don't use host cache and a
> block device reads data directly from userspace.

We simply think the behavior is correct. If you want to be sure data is
on disk you have to call fsync.

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